Virtually every vehicle operator periodically gets a flat tire in a location remote from a service station or garage. This requires a change to a spare tire. Unfortunately, a great percentage of vehicle operators at one time or another will discover to his or her dismay in such an emergency that the spare tire is also flat or grossly underinflated.
Attendants in service stations, garages and the like rarely ever check the spare tire when checking the "in use" tires unless asked to do so by the vehicle's operator. The operators themselves generally conform with the old saying "out of sight, out of mind." Consequently, the great majority of spare tires go without closely spaced apart pressure checks or are never checked at all until they are actually needed as a replacement for a flat tire.
Pressure indicators of the type disposed directly on the valve stems of spare tires as in the prior art provide no solution to this problem because such indicators are "out of sight" along with the spare tire and the same forethought is required to check the indicators as is required to actually check the air pressure with a pressure gauge.
Therefore, one of the principal objects of the present invention is to provide an indicator means in the passenger compartment of an automotive vehicle which is interconnected with the valve stem of a remotely located spare tire to, at all times, keep the operator of the vehicle informed as to the air pressure condition of the remotely located spare tire.
Another object of the invention is to provide a virtually inescapable visual or audible indicator means in a relatively close proximity to the vehicle operator which immediately informs the vehicle operator when the air pressure in the spare tire reaches a level operator when the air pressure in the spare tire reaches a level which is too low for safe use of the tire.
A further object of the invention is to provide a valve connection from the indicator means to the valve stem of the spare tire which automatically shuts off when the pressure in the tire reaches a predetermined low level, 25 PSI, for example, in the event of leakage between the shut-off valve and the indicator means in the passenger compartment.